Journal of the Australian Ceramic Society最新文献

As society ages, the treatment of osteoporosis has become an issue that must be solved. In this study, we evaluated the effects of hydroxyapatite, βTCP, strontium calcium-deficient apatite, and strontium βTCP on osteoclasts using osteoporosis model zebrafish. Calcium-deficient strontium nanocrystalline apatite was achieved by mechanochemical synthesis. Characterization of the synthesized samples was analyzed by XRD, FTIR, and TG/DTA. In an experiment where zebrafish, used as a model for osteoporosis, were exposed to various apatites, the morphology of osteoclasts was observed by evaluating their scales. The apatites to which the zebrafish were exposed were suggested to influence the differentiation of osteoclasts.

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This retrospective clinical study aimed to investigate the long-term clinical performance of glass-based ceramic onlay restorations in terms of survival rate, types of failure, and patient satisfaction over an eleven-year follow-up period. Glass-based ceramics are increasingly preferred in restorative dentistry for their mechanical resilience and superior optical properties, which meet the requirements of modern minimally invasive and esthetic approaches. A total of 115 indirect glass-based ceramic onlay restorations, placed between 2012 and 2023, were retrospectively analyzed. Clinical records were reviewed to determine restoration survival and failure types. Patient satisfaction was assessed using a numerical rating scale ranging from 0 to 10. Statistical analyses were performed to evaluate potential influencing factors such as marginal integrity, tooth location, and restorative procedures. The overall survival rate was 87.9%. The most common causes of failure were ceramic fracture (6.0%) and adhesive debonding (5.2%). Patient satisfaction was generally high, with mean scores above 8. Tooth position and marginal adaptation were statistically significant factors affecting restoration longevity. Glass-based ceramic onlay restorations demonstrated high long-term clinical success and patient satisfaction, supporting their use as conservative and esthetic alternatives to full-coverage crowns. These findings suggest that such restorations can be reliable long-term treatment options, provided proper material selection, tooth preparation, and bonding protocols are followed.

In this research, a metallic layer (NiCrAlY) was applied on the low-carbon Ni-based superalloy IN-738LC, as substrate. Subsequently, a gradient ceramic layer comprising mullite and yttria stabilized zirconia (YSZ) was coated on the NiCrAlY metallic layer. Finally, an outer ceramic layer, consisting of 100% mullite was sprayed as top coat. All coating layers were applied using the air plasma spraying (APS) method. The gradient coatings were subjected to isothermal oxidation at 1000 ℃ for 50 and 100 h to investigate their high-temperature properties. The findings revealed that the thickness of the thermally grown oxide (TGO) layer increases with the increasing oxidation time. The thicknesses of the TGO layers were 5 and 7 ± 0.3 μm at 50 and 100 h, respectively. According to energy dispersive spectroscopy (EDS) analysis, the oxides formed in the TGO layer mostly consist of aluminum oxide along with a few amount of spinel oxides. This indicates the superior resistance of the gradient coating to the oxygen penetration and forming harmful oxides. The hardness values of the gradient ceramic layer, comprising mullite and YSZ, were 880 and 995Hv before and after oxidation, respectively. However, the hardness values for the monolithic mullite and YSZ ceramic layers were lower. The porosity content of each layer was also examined. In the gradient layer, the porosity level was 16% which was significantly lower compared to those of the monolithic YSZ and mullite layers. This low porosity content in the gradient layer was a key factor contributing to its excellent performance under high-temperature oxidation, demonstrating a marked superiority over conventional hybrid coatings.

Water pollution, particularly from methylene blue (MB), has been escalating significantly over the years, necessitating enhanced management to avoid chronic consequences. Here, red soil (RS), which is relatively easy to find in nature, is mixed with melamine as carbon nitride (CN) source to make CN/RS composites as a promising MB waste degrader. It was found that, CN/RS3 has shown the best degradation performance of 88.50% without stirring assistance in order to follow the environmental conditions. In addition, all sample showed a decreasing crystallite size and crystallinity index as the increasing of RS composition. The degradation performance is strongly supported by the decrease of crystallite size, suitable ((Delta LO - TO) ) as a representation of optical phonon vibration ~323 cm⁻¹, as well as slightly ({E_g}) increasing ~3.5 eV. The average pore size of CN/RS3 has been investigated from SEM result and obtained diameter (469 ± 0.20) μm. IoT was also conducted as fresh technique for monitoring CN/RS performance during 2500 minutes in real-time, where the optimal performance is achieved at pH 6.63 with temperature at 26.86 °C.

Sustainable production of hydroxyapatite (HAP) from animal bone waste offers an eco-friendly and cost-effective route for material development. Camel femur bone, although abundant, has been less studied compared to bovine bone. In this work, HAP was extracted from camel and bovine femur bones by thermal decomposition (650–1000 °C) and characterized by FTIR, XRD, XRF, SEM, and TGA. Antibacterial, antibiofilm, and anti-inflammatory activities were evaluated against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Pseudomonas aeruginosa (P. aeruginosa). FTIR and XRD confirmed 650 °C as the optimal calcination temperature, yielding phase pure HAP with preserved functional groups. XRF showed Ca/P ratios close to stoichiometric HAP (1.64 for bovine, 1.63 for camel), along with bioactive trace elements (Na, Mg, Sr, Fe, Zn). Camel derived HAP displayed larger crystallite size, higher thermal stability, and stronger antibacterial activity, particularly against P. aeruginosa. Both sources inhibited biofilm formation by over 79% and stabilized proteins up to 40%. Unlike previous studies focusing only on synthesis or structural characterization, our work provides the first systematic comparative evaluation of camel and bovine derived HAP, linking bone origin to antibacterial, antibiofilm, and anti-inflammatory behavior. Further biological validation is needed before considering biomedical or dental applications.

In current work, (75–1.5x) Li₂O-(25+0.5x) B₂O₃-x Bi₂O₃ glass system, (x = 20, 25, 30, 35, 40, 45, 50 mol %) was investigated for neutron and gamma radiation shielding applications. Mass attenuation coefficients (µ/ρ) of the samples over photon energies from 0.020 up to 1.524 MeV have been derived from WinXCOM, FLUKA, Geant4, and PHITS softwares. Half-value layer (HVL) and mean free path (MFP) of 50 Bi₂O₃-50 B₂O₃ glass sample have been compared to SCHOTT AG commercial glass shields. Elastic properties are determined using Mackenzie-Makishima (M-M) and bond compression (BC) models. The exposure buildup factor (EBF) and energy absorption buildup factor (EABF) of the samples as a function of photon energies for multiple penetration depths: 1, 2, 5, 10, 15, 20, 25, 30, 35 & 40 mfps were determined using the geometric progression (G-P) fitting method. Effective atomic number (Z_eff), effective electron density (N_eff), and linear attenuation coefficient (µ) values over photon energies 0.020 ‒ 1.524 MeV span were derived from µ/ρ values. Total thermal neutron attenuation (σ_T) and fast neutron removal cross-sections (Σ_R) of the samples have been calculated based on the cross-sections of their constituent oxides. The neutron shielding percentages at different sample thicknesses were calculated based on σ_T and Σ_R. Ionic character factor and covalent character factor of the glasses were estimated based on the Pauling electronegativity of their component oxides. µ/ρ, µ, EABF, EBF, Z_eff and N_eff have been enhanced or reduced by the absorption edges of Bi, photoelectric absorption, Compton scattering, and pair production. Li₂O-Bi₂O₃-B₂O₃ glass system shows greater thermal neutron radiation shielding (σ_T = 12.3649 cm⁻¹ − 13.4853 cm⁻¹) than concrete. 50B₂O₃-50Bi₂O₃ displays superior gamma and fast neutron shielding capability (∑_R = 0.12174 cm⁻¹) compared to other glass systems and concrete. Increments in boron and bismuth oxide concentrations reduce elastic moduli e.g. Y_bc: 113.0526 GPa − 85.5033 GPa. Poisson ratios (0.2552–0.2800) indicate low structural connectivity.

Fluid catalytic cracking (FCC) devices in petrochemical industries and refractories experience challenges in locating commercial items that possess well-suited thermo-mechanical characteristics for operating at temperatures below (< 900 °C). Since colloidal silica-bonded refractories often begin to densify at temperatures above 1200 °C, applying sintering additives to accelerate these densification processes is a highly interesting technical approach. This study aims to assess the performance of high alumina refractory castables that incorporate a sintering additive based on magnesium borate, as well as colloidal silica binder sources. This study examined the consequences of including magnesium borate as a boron source to high alumina colloidal silica-bonded castable sintered at temperatures as high as 1200 °C. Measurements of apparent porosity, cold modulus, and hot modulus of rupture evaluated the compositions. XRD and SEM investigations have identified the reaction processes and phase evolution relevant to the high temperatures. Incorporating 1.5 wt% of the sintering additive into the castable significantly enhanced the hot modulus of rupture (39.5 MPa) and cold modulus of rupture (43.2 MPa) following fire at 815 °C for 5 h. An enhanced refractory was also produced by combining nano-bonded silica with magnesium borate as a sintering additive. This combination exhibited a transient liquid formation at a higher temperature, leading to high mechanical strength at 815 °C and 1200 °C.

This study improves the predictive accuracy of machine learning (ML) models for ceramic glaze gloss by integrating advanced feature engineering and data preprocessing techniques. Using a dataset of 1,250 glaze samples with chemical composition and gloss values, we systematically evaluated different preprocessing strategies and ML architectures. A Multi-Layer Perceptron (MLP) model was optimized by adjusting layers, nodes, optimizers, and activation functions. Baseline models trained on raw data exhibited high Mean Squared Error (MSE) values, with a minimum of 756.87, indicating their limitations in capturing non-linear relationships. Applying scaling techniques, particularly the Power scaler, reduced the MSE to 364.08 by addressing data skewness and sparsity. Feature engineering further improved accuracy by incorporating molar ratios (RO, R₂O, RO₂, R₂O₃) based on the Unity Molecular Formula (UMF) and relative alkali/alkaline earth oxide ratios. The Total-Normalized Method (TNM), which retains variability across all oxide groups, outperformed the Alkali-Normalized Method (ANM), achieving the lowest MSE of 87.37 when combined with optimized hyperparameters. The Adam optimizer and ELU activation function demonstrated superior performance, effectively handling non-linearities in high-gloss regions. Residual analysis confirmed enhanced predictive reliability, with significantly reduced errors in complex gloss distributions. This study highlights the importance of preprocessing and feature engineering in ML-based ceramic material modeling and provides a framework for extending these approaches to other material systems.

Compositional diversity in bioceramic root canal sealers creates significant variability in fundamental physicochemical and biological properties, making the ideal material selection for clinical success uncertain. The purpose of this study was to compare four bioceramic based sealers, and an epoxy resin-based sealer, in terms of physicochemical properties. In this in vitro study, solubility, pH, dimensional change, radiopacity, flowability, microhardness and setting time tests were applied to the samples prepared using four different bioceramic based root canal sealers (EndoSeal MTA, MTA-Fillapex, Tech BioSealer Endo and Well-Root ST) and AH Plus Jet, an epoxy resin-based root canal sealer. Flowability, setting time, solubility, radiopacity, and dimensional stability were evaluated in accordance with International Standards Organization (ISO) 6876 standards. pH and microhardness were tested with reference to previous studies. Data were compared using ANOVA and post hoc Tukey HSD statistical tests. MTA-Fillapex did not show complete setting even after weeks. Although the flowability value of Tech BioSealer Endo was lower than the other groups (p ≤ 0.05), it was observed that its microhardness value was the highest (p ≤ 0.05). The radiopacity of EndoSeal MTA was higher than Well-Root ST and Tech BioSealer Endo (p ≤ 0.05) but lower than AH Plus Jet (p ≤ 0.05). All tested sealers showed shrinkage and the shrinkage rate of EndoSeal MTA, Well-Root ST and Tech BioSealer Endo were in compliance with ISO standards (ISO (6876:2001). While the tested bioceramic-based sealers exhibited different physicochemical properties, it was observed that they did not meet ISO (6876) standards in some respects.

Mussel shells, commonly discarded by restaurants, households, and aquaculture facilities, cause environmental problems due to their slow decomposition and improper disposal, such as dumping into the sea or landfills. As part of sustainability-oriented strategies, reusing such biogenic waste as a raw material offers both ecological and economic benefits. This study investigates the potential of mussel shell powder as a sustainable calcium oxide (CaO) source to replace calcite in opaque, matte, and transparent ceramic tableware glazes X-ray fluorescence (XRF) analysis revealed that, apart from their organic content, the chemical composition of mussel shells is highly similar to that of calcite. While calcite naturally contains the calcite calcium carbonate (CaCO₃) phase, mussel shells are composed of calcium carbonate and its polymorph, aragonite. During firing, the aragonite phase transforms into calcite and subsequently decomposes into CaO. Thermal and phase analyses indicated that the incorporation of mussel shell promotes anorthite formation, resulting in improved microhardness and enhanced thermal stability of the glazes. Additionally, the use of mussel shell did not adversely affect surface gloss or color; all compositions exhibited ∆E values below 1, indicating a negligible color change. Overall, mussel shells can be effectively utilized as an eco-friendly and cost-efficient CaO source in glaze formulations. This approach contributes to waste valorization and supports the development of sustainable ceramic materials.

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